


A Demonic Love

by ALPHAwolf



Series: The Love Life of Demons' [1]
Category: Kuroshitsuji | Black Butler
Genre: Anal Sex, Blow Jobs, Dark Magic, M/M, Smut
Language: English
Status: Completed
Published: 2016-08-12
Updated: 2016-08-12
Packaged: 2018-08-08 07:29:57
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,864
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7748695
Author URL: https://archiveofourown.org/users/ALPHAwolf/pseuds/ALPHAwolf
Summary: <blockquote class="userstuff">
              <p>A deal made between a demon and the Phantomhive family before Black Butler began. Ciel's meeting with the demon that came to be known as Sebastian was no coincidence. A sinful night and black magic bonds sealed the child's fate before he even knew such monsters existed.</p><p>(edited 3/18)</p>
            </blockquote>





	A Demonic Love

**Author's Note:**

> All the usual disclaimers :) Don't read if you don't like ;p

The full moon glowed white against a black sky, it's dim luster the only light in the room. It shone in through the huge study window behind the earl of the Phantomhive household, outlining the large leather chair the human sat casually in.

A crimson eyed demon stood in it's hellish form before the family head, grinning dangerously. It’s sharp fangs glimmered in the soft light, a quiet kind of growl vibrating in what must have been it’s throat. It almost sounded like a cats purr. 

It was keen to hear this human’s reason to have released him from hell using such evil and forbidden 'magic'. Just the scent of his tainted soul made it want to salivate. Such a dark, delicious smell.

The man certainly didn’t look like the typical type to take part in a Satanic ritual, such a handsome and beautiful young man with an alluring soft smile. Clearly looks were deceiving if the body laying with an open chest on the floor was anything to go by. The blood which had been shed for the pentagram drawn beneath the demon. 

"A pleasure to meet one of your kind, Worker of Satan." The creature laughed at this. Such a brave human, but surely the sound of his trauma inducing laughter would set him straight. To the monster’s surprise he didn't even flinch, but continued to stare unwavering straight into his scarlet eyes. It was a little irritating.

"The pleasure is mine.” It hissed, voice still somehow inhumanly beautiful. “Please, enlighten me as to why you have called upon someone such as myself." The devil’s thin tongue licked it’s lips threateningly, but the man behind his desk only smirked at the sight of the pink organ poking out from between it’s canines.

"I'd like to make a deal in exchange for my soul." The demon hummed in approval, the black shadows engulfing it growing in hungry anticipation. The human smiled. Evidently things were going his way, and the creature did not approve of that at all.

"You would like a contract? But of course, what are your wishes before I consume your soul~?" The human stood, his face no longer shadowed, each feature lit by the moonlight. He had a smug but gentle look, a beauty spot under his left eye, bluish-grey hair, and green-old-gold irises.

"So rushed?" The man asked with an almost suggestive smile as he walked over, not in the least intimidated by the swirling display of shadows before him as he stepped over the corpse. "How about we become acquainted first? My name is Earl Vincent Phantomhive, evil nobleman, Guard Dog to the Queen, and lord of this estate." He held his hand out for the demon to put it’s own in.

Confused and intrigued by the odd human the hellish creature put it’s black gloved 'hand' in the man’s. Vincent smirked and lifted it to his lips, placing a soft kiss on the bony, leather clad knuckles. The demon froze. Either this human was insane, or... Insane.

"And you?" The monster regained it’s composure in less than a second.

"A mortal being like yourself has no right to such information." The human smirked and let go of his hand.

"Very well then, back to business. How dull." He travelled back to his seat, sitting regally.

"What is it you want of me in exchange for your soul, evil nobleman." Vincent gestured for him to sit in the empty chair before him, but the demon made no move to do so.

"In exchange for my soul you will serve my son, Ciel Phantomhive, for the rest of your immortal life." The demon was about to laugh when he was interrupted. "I and my wife will be killed by the Queen's order at any moment, and I wish for my son to continue living. You will save him from death, form a contract with him, and then turn him into a demon when the time comes." The creature gaffawed, the sound somewhat like nails clawing down a blackboard or cats singing. What an amusing human!

"You care not for your wife sleeping upstairs?" He asked, purring delightfully at the notion. Vincent looked at him thoughtfully a moment.

"No, not really. Arranged marriages are a bore. My son will continue the Phantomhive name, an unwitting agent of evil." Vincent looked down at the sapphire ring on his finger with a fond smile. The demon grinned, his red orbs shining.

"You are quite the monster, My Lord."

"But of course, I am an Evil Nobleman after all, one of the few Aristocrats of Evil." The demon decided not to comment. Truly this human’s character was puzzling. It was as if he actually thought his evil rivalled the demon's own.

He rubbed his chin and shamelessly looked the devil up and down. 

"While serving my son you will need a more appropriate attire, and a more conspicuous appearance." The ex-angel smirked again, humoring the other if only for his own amusement. 

"But of course." The shadows around him twisted, starting to fade as he stepped forward out of the darkness. He shifted dramatically from his leather demon attire to that of a common butler, taking on a more human appearance. His crimson eyes still shone, ebony black hair framing his thin face. The shapeshifter had taken some features of the man before him, fitting them to his own.

The aristocrat smiled, his eyes running over the demon’s attractive frame.

"Is this sufficient?" The creature asked, feigning innocence.

"Very nice, but I believe I need a closer inspection." He gestured for the beast to come to his side. Now suspicious the demon slowly made his way over to the man. Vincent looked over him closely, his hand starting at the demon’s silky black hair and softly dragging down his chest. Such treatment from a human, or any other being, would have usually meant their doom, but the demon only stood perfectly still, not willing to step away from the sinful sensation.

Vincent pulled the fallen angel down by his collar, looking straight into it’s scarlet eyes, clouded with godless lust.

"How intriguing." He commented, bringing the demon’s face closer to his own. "Shall we seal the deal?" He asked in a hot whisper tight into the monster’s ear.

The being from hell shivered.

"Where is it you wish for your contract seal, my Lord?" He asked sexily, faking that ignorance the human seemed to feed off.

Vincent suddenly pulled the demon onto his lap, the humanoid’s legs open over his. He took the creatures hand and slowly peeled off it’s white glove, before undoing his pants and bringing the devil’s hand to the spot just below his navel, right above his member.

"Right here." He whispered sexily, "But what's the rush? How about we get to know each other a little better first?" With that he bought the demon’s lips to his own in a hungry kiss. The devil made an odd noise in shock, but quickly recovered and moved his lips skillfully against the human’s.

Their open mouths fit perfectly against one another, both men experts of pleasure. Vincent pulled the demon closer by the waist, his other hand slowly making it’s way up the creature’s thigh, towards his rear.

The ravenette's arms wrapped around the human’s neck. He couldn't help it. Such sin was soooo delicious. What they did was so forbidden, yet the taste so deludedly devine. Adultery, homosexuality, bestiality (Vincent being the beast of course). It made him shiver in delight.

Vincent's hand cupped the cheek of the demon’s ass, staring to fondle and grope it. The monster purred, his thin wet tongue slipping out to meet the bluette's. The two viciously fought in their mouths for dominance, and he was confident there was no way the man before him could win. He’d bested both succubus and incubus with his tongue. 

Their lips continued their battled for control as Vincent smirked into the kiss, his hand going up the demon's shirt slowly.

"Ahh~!" Vincent softly toyed with the smooth nipple under the ex-angel’s white shirt, having already undone his vest, effectively winning the battle. "H-how unsophisticated~ you play dirty human." The lord only smirked darkly, his lips latching onto the demon’s neck. "Ahhh-ha~" Vincent chuckled and removed the fiend’s tail coat, beginning to undo the buttons of his shirt. The demon chuckled. "You waste time, My Lord." His clothes turned to shadows in the next moment, leaving him bare, bathing in the moon’s light on the Lord’s lap.

Vincent smiled, leaning back in the chair to observe the monster’s perfectly toned body. The immortal’s pale skin shone, his entire body without a flaw. Phantomhive licked his lips, looking up at the demon.

The fallen angel's smirk disappeared, a shade of light pink dusting his cheeks in the illumination of the moon. The Lord chuckled.

"Well, demons are not that far from human’s in behaviour I see." He let his fingers trail over the other’s cheek. His skin was warm to the touch against the man’s cold gloved hand.

The demon would have said something, anything to deny the statement, but again that sinful touch caressed him, silencing his suddenly meaningless comment.

Vincent's hands gripped his behind and he kissed the demon passionately, the ravenette's breath sucked right out of him, not that he needed it. A distorted dark feeling poured over him with the filthy kiss, the taste intoxicating just like the scent of his soul. The man’s hands massaged his behind, traveling closer to his entrance with every movement.

The demon moaned into his mate's mouth as his entrance was touched softly by the man’s bloody, gloved hands, then abandon. Their lips parted reluctantly, the human in need of oxygen. How drear. 

"You want me to put them in?" He questioned breathlessly, although he already knew the answer. the demon nodded, lust ruling his puppet body. The human smirked and groped the demon’s ass roughly, one hand abandoning it’s place and coming in front of the creature’s mouth. He pointed two fingers before his wet parted lips, no words needing to be spoken as the demon pulled the glove off with his teeth and took the bare skin into his mouth, hungrily salivating the digits.

Vincent watched, leaning on his other hand in a regal manner as the male seemed to enjoy licking his fingers. The human looking beast ceased after giving them one last long lick, his mouth left open as he looked into Vincent's eyes lewdly.

"Such a talented tongue," He commented, moving his lips closer to the demon's ear, "We will have to put it to even better use later." The lord whispered seductively.

"Ahh!~" Vincent's fingers thrusted into the demon's tight hole, making him throw his head back in ecstasy. This now gave the human full access to his neck. "Nggh~!" He bit and licked up the monster's exposed throat, the nameless beast welcoming the harsh bites and rough stretching inside him.

The ravenette moaned as Vincent bit particularly hard on his jugular, drawing blood.

"A masochist hm?" He chuckled and whispered darkly into the demon’s ear. "I will be sure to show you the meaning of pain and pleasure then." With that he bit down on the monster's ear, drawing a sinful moan from the other’s lips.

Of course the demon could choose to not feel all these sensations as much as he did, but something about this human made him want to fall into impure ecstasy in the man’s cold embrace.

The devil’s hips moved against his new mate’s hand, desperate for further penetration. Vincent bit down on his nape, slowly licking up the blood from the wound. It reminded the devil of one of felines licking up milk.

The man removed his fingers, causing the demon to whimper. This human left him a slave to pleasure.

Vincent inspected his glistening fingers, which now had veins of blood streaking them. He smirked and licked his fingers clean of the crimson and slick as the demon shivered from the sexy display.

Suddenly Vincent lifted him up, pushing his body against the desk and standing. The man's hands ran all over him, the nobleman's mouth latching onto his nipples and sucking softly before biting the nub.

"Nngh-!" The demon pressed up against his mate’s body, arms wrapping around his neck as he desperately rubbing his erection against the other’s.

"No need to hold back your voice, I wish to hear those sinful noises pass your lips." He trailed a finger over the creature’s bottom lip.

Their mouthes latched onto one another, both kissing passionately, almost lovingly, as if either knew of such a thing.

Vincent's hands came to caress the devil’s behind yet again as his partner's hands travelled down his chest and stomach, pulling his already undone pants further down to reveal his hard manhood. It was so... large, for a human.

"Enjoying the view?" Vincent asked, catching the demon’s stare. The incubus like male laced his fingers into the other’s grey-blue hair.

"Yes." What did he have to be ashamed of with admitting his delight? He’d abandoned heaven for such stupid rules.

Their open mouths connected once again, both of their bare erections rubbing together, the two dripping pre-cum. 

"Turn around and bend over." Vincent demanded sexily as they parted, both panting. The demon shivered and nodded, following the command as he placed his hands flat on the study desk and poked out his ass. The human's fingers ghosted over the surface of his behind, his hands leaving a cool sensation on the demon’s burning skin. He moaned from the touch he barely received as the lord chuckled.

"So desperate for my touch? Harlot." The sound of a slap filled the room and the creature moaned after receiving a sharp hit to his ass. The human chuckled at the reaction and started to fondle his behind yet again, his member resting between the demon's cheeks, but not entering. The ravenette whimpered and pushed back against him wantonly.

Vincent parted his cheeks and bent over the demon, lips right by it’s ear. 

"You want it?"

"P-please~ Master~" Vincent grinned, and with one quick thrust buried himself to the hilt in his 'mistress'. The demon screamed, his perfect voice filling the room. It wasn't hard to believe this dark being was once an angelic member of God's choir.

The earl didn't bother waiting for the demon to get used to his size and began thrusting in and out harshly. The creatures voice echoed through the study. It would be a miracle if the entire mansion didn't wake from the sounds.

The nameless one moaned, his entire body shaking as he struggled to stay supporting himself. Vincent seemed to laugh at the effort and thrusted in so hard the demon's body went limp on the desk. The human continued to slam in, each time harder than the one before. The demon clawed against the desk, saliva dripping from his mouth onto the wood top.

Vincent moaned as the devil’s walls tightened. He could have cum right then, but he was determined to outlast the satanic creature. One of his hands came to the demon’s crotch and began to softly touch the hard appendage. A whimpered moan followed, the lithe male’s body like a rag doll as he tried to rest up on his elbows.

As he became accustom to the human’s rhythm- touch, thrust, pump, touch, thrust, tug, lick, touch, he was able to gain his balance. He moaned into the air, leaning on his forearms, head thrown back. Now he could move his hips back against Vincent to meet his thrusts. As soon as he did the tip of the other’s member pressed against something soft deep inside his human body. Stars danced across his vision and he moaned loud enough for it to be labelled as yelling. Torturously the other hit that spot again, then deliberately missed, then hit it again.

The two moved against each other, going  faster and with each thrust. 

The moon illuminated their sweat, dripping down their glowing exposed flesh like falling stars. While the demon was completely bare Vincent had somehow managed to stay with only his pants pulled down enough to release his cock.

The devil’s body convulsed, his muscles locking as his mouth hung open. His vision blacked out, and something in his abdomen tightened deliciously. Cum shot from his human member into his mate's hand as he arched his back perfectly. The other grunted as the walls around his cock clenched, but refused to orgasm.

The demon's body fell limp as he panted, white stars dancing under his eyelids. Vincent tutted.

"How shameful," He pulled out, making the creature whimper, and sat back down in his chair, "Losing yourself before a pitiful human." He mocked with a smug smile "I'm still yet to reach my climax. You'll have to do something about that."

The demon looked behind him at the man sitting regally in his chair, his erection high out of his trousers.

"Remember how I said something about putting your mouth to good use?" He asked, smirking. Instantly recovered the demon replied by licking his lips with a sly smile.

Vincent watched closely as the creature turned around, cum dripping from it’s alive cock once again, and kneeled before him. The demon looked up at him with a submissive smirk and Vincent lifted his cum covered hand to his lips in a bored fashion, looking down as him with smiling eyes as he licked the translucent white off his fingers and palm. The demon moaned and started to touch his own erection, his knees open wide on the ground below Vincent. The lord chuckled at the seductive sight and took the ravenette's hair in his hand roughly, bringing it’s head to his open crotch.

"Suck." He commanded. The demon purred and took the entire of his throbbing man-hood in it’s mouth to the hilt, deep-throating him as it moaned like a whore. Vincent's grip on his raven hair tightened and he thrusted into him mercilessly, cock hitting the very back of the monsters throat. The demon smiled and sucked harder, his tongue twisting around and running all along the appendage inside his mouth.

Vincent moaned, his head back against the chair as he gripped the hell-sent's locks so tightly it would have ripped straight out of a humans head, but the creature loved it.

The ravenette licked the long, thick member, marvelling at how it had ever fit in him and treating it like a child would a sweet treat. Though he had never been one for human sweets the taste of this human's seed was so much like his soul. Strong and bitter. The demon sucked more on the tip, tongue probing the small hole, trying to coax more of the delicacy out.

The demon smirked, a plan to taste the full deliciousness of his 'master' formed. He placed his hand just above his new master’s member, where he had ordered his seal to be, and started to suck painfully slow as he marked him. It burned like an unquenchable fire, setting the lords every nerve haywire. Vincent moaned at the overwhelming sensation, and his own release hit like a freight train.  

The demon sucked like leech through it, refusing to let even a drip escape his lips. The bitter taste was so delicious it brought about his own second release, but even as he came he drank without fail.

Once every last drop was sucked from him the demon pulled away reluctantly. Vincent was already partially recovered, looking down at him with a self-satisfactory smirk. Pink dusted the demon's cheeks.

"Hm, I like the look of it." He commented, finger tracing the lines of the black star encased in a double circle below his navel. The demon smiled and laid his head on his crossed arms atop of the earl’s lap.

The lord lifted the creature’s hand which had the contract on the back to his lips and kissed the pentagram's centre.

"Now your mine till my demise, demon," He said smirking "Mistress to the Queen's Guard Dog." The demon scrunched up his face.

"You seem more like a cat then a dog to me, dogs are filthy creatures." Vincent laughed.

"They are, aren't they?" His hand ran through the demon’s hair fondly. The creature sat content, smiling softly up at him.

"Does this mean I'll be coming back to serve you nightly 'Master'?" Vincent leaned down, the demon looking up at him hopefully. 

"If you didn't," he whispered, ghosting the ravenette's lips, "what kind of a butler would you be?"

The two's lips connected once again in a passionate kiss, condeming them both, and nothing had ever tasted more perfect on the demon’s tongue. 

 

§

 

Sebastian's eyes snapped opened.

He lay alone in his room, the head butler’s chamber in the Phantomhive mansion. It was night outside, the full moon high above in a black sky. He sat up, an uncomfortable sensation between his thighs.

Sleep was a luxury he sometimes delighted in, but whenever he did it was the same outcome- more washing.

He stood, stripping into a new uniform, thankful the sheets didn't need changing. Truly human reactions to arousal, such as ejaculation in ones sleep, was a bothersome thing.

He looked towards the midnight moon. His new Master was not to be woken for hours. No one would notice if he slipped out. Sebastian smiled and quickly left the room, travelling silently down the hall and through a few more doors to the front yard.

He took a white rose from one of the gardens rose bush, the flower open wide in the illusion that the moon's illumination was sunlight.

A cat meowed from his feet, and he picked the black feline up, taking his time to pet the creature favourably. Eventually he put it down, the cat running off to prey on small animals of the night.

He left the Phantomhive estate, taking barely any time to arrive at his destination. A cemetery on the outskirts of London, a place where only noblemen and Lords could afford to be buried.

Sebastian stood in front of an obsidian grave stone, decorated with thorny roses.

The ravenette demon looked up at the moon and back down at the shining gravestone, kissing the white rose in his hand. It’s petals bled black at the touch of his sinning lips till the entire rose was dark as a raven’s feathers.

He placed the rose on the grave and sat, his ungloved hand taking a fistfull of dirt from the grave and turning it to ash, watching the wind blow it away.

The demon sat silently with a blank expression, looking down at the black flower. Before he knew it the sun was rising over the rolling hills. Sebastian sighed and stood, smiling down at the grave fondly.

"I will see you in hell, my eternal Master." With that he turned and left, traveling back to the Phantomhive estate.

The sun rose over the black grave stone, lighting it’s golden words.

 

 _Earl Vincent Phantomhive_  
_The Queen’s loyal Watch Dog_

 

§

 

"Hohoho~" (Tanaka sees everything).

**Author's Note:**

> Now if you're up for a laugh go back and re-read it imagining David Attenborough's voice XD  
> Remember to Kudos!


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